Electron discharge device



June 28, 1949. l R.- R, BACK 2,474,211

ELECTRON DISCHARGE DEVICE vFild May '20, i947 S INVENToR 0' l v EN@ -ATT RNEY Patented June 2s, 1949 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE Delaware Application May 20, 1947, Serial No. 749,142 In Great Britain July 7, 1939 Section 1, Public Law 690, August 8, 1946 Patent expires July 7, 1959 3 Claims.

This invention relates to thermionic valves adapted to operate at high voltages for example as a rectifier for the supply voltage to a cathode ray tube of an oscillograph or television receiver.

The valve of the invention comprises an anode presenting an unbroken convex surface to a tubular indirectly heated lcathode which is disposed perpenducular t`o the axis of the anode. Preferalbly the cathode is mounted upon a lead-in conductor sealed in the envelope opposite the stem. The cathode may be supported in plates of metal or of insulating material such as mica upstanding from a disc shield supported upon the stem. A further feature is the provision of end shields for the cathode lfor shielding the anode from the projecting parts of a heater passing through the cathode.

A valve embodying the invention is shown in the accompanying drawing of which Figs. 1 and 2 are two views at right angles of the electrode structure, Fig. 1 being a sectional view.

Referring to the drawing, I is a glass stem in which wires 2, 3 and 4 are sealed in the same way. Wire 2 supports a flanged metal disc 5 on which are xed by welding a pair of arched metal end shields 6, 'I for a tubular indirectlyheated cathode 8. The cathode is supported parallel to disc 5 by means of mica plates 9 which are in turn supported in slots in the end shields 6, 'I. The cathode and one of the legs of the internal heater are connected to shield 6 by wires I0, II respectively and leading-in wire 2 serves for the external connection to these elements. The other heater leg is connected to a wire I2 which passes freely through an aperture in the disc and is welded to leading-in wire 4. The wire 3 sealed in the stem `carries a small metal plate I3 to which getter material is applied.

The stem I is mounted in a glass bulb in the usual way, means being provided for evacuation. In the closed end of the bulb a leading-in Wire I4 is sealed. This wire is provided with a sheath (Cl. Z-27.5)

2 I5 in the form of a glass tube, and carries a dished metal anode plate lr6. This anode plate is co-axial with the disc 5 and stem I and presents a smooth convex surface to the cathode 8. The heater for the cathode is effectively screened from the anode by the end shields 6, 1 and the stem is shielded from bombardment and overheating by the disc 5.

What is claimed is:

1. An electron discharge device comprising an indirectly heated cathode mounted substantially transverse to the axis of said device, a heater passing through said cathode and projecting through the ends thereof, an anode having a transverse dimension substantially equal to a transverse dimension of said cathode mounted in spaced relation from one side of said cathode, and shield means mounted adjacent said cathode, said means including a base shield positioned from said cathode on a side remote from said one side and end shield means extending from said base shield and interposed between said anode and projecting parts of said heater.

2. An electron discharge device according to claim 1 in which said base shield constitutes a metal disc and said end shield means comprises g1; least one arched metal shield secured to said 3. An electron discharge according to claim 1 in which said cathode is insulatingly supported on said base shield.

RAYMOND RICHARD BACK.

REFERENCES CITED The follorwing referenlces are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,956,396 Moran Apr. 24, 1934 2,107,945 I-Iull et al Feb. 8, 1938 2,113,005 Smith Apr. 5, 1938 

